// seccomp or a similar technology.
func checkPidfd() error {
	// Get a pidfd of the current process (opening of "/proc/self" won't
	// work for waitid).
	fd, err := unix.PidFDOpen(syscall.Getpid(), 0)
	if err != nil {
		return NewSyscallError("pidfd_open", err)
	}
	defer syscall.Close(int(fd))

	// Check waitid(P_PIDFD) works.
	for {
		_, _, err = syscall.Syscall6(syscall.SYS_WAITID, _P_PIDFD, fd, 0, syscall.WEXITED, 0, 0)

import "syscall"

func PidFDSendSignal(pidfd uintptr, s syscall.Signal) error {
	_, _, errno := syscall.Syscall(pidfdSendSignalTrap, pidfd, uintptr(s), 0)
	if errno != 0 {
		return errno
	}
	return nil
}

func PidFDOpen(pid, flags int) (uintptr, error) {
	pidfd, _, errno := syscall.Syscall(pidfdOpenTrap, uintptr(pid), uintptr(flags), 0)
	if errno != 0 {
		return ^uintptr(0), errno
	}
	return uintptr(pidfd), nil

	n = int(r0)
	if e1 != 0 {
		err = errnoErr(e1)
	}
	return
}

// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT

func PidfdOpen(pid int, flags int) (fd int, err error) {
	r0, _, e1 := Syscall(SYS_PIDFD_OPEN, uintptr(pid), uintptr(flags), 0)
	fd = int(r0)
	if e1 != 0 {
		err = errnoErr(e1)
	}
	return
}

//sys	ProcessVMWritev(pid int, localIov []Iovec, remoteIov []RemoteIovec, flags uint) (n int, err error) = SYS_PROCESS_VM_WRITEV

//sys	PidfdOpen(pid int, flags int) (fd int, err error) = SYS_PIDFD_OPEN
//sys	PidfdGetfd(pidfd int, targetfd int, flags int) (fd int, err error) = SYS_PIDFD_GETFD